A distance sensor positioned on a vehicle for registering vehicles traveling ahead is described in German Patent No. 42 42 700, working, for example, on a radar or infrared basis. The radar sensor can be, for example, a building block of a vehicle luxury system ACC (adaptive cruise control), in which data about the distance from, and the relative speed to other vehicles and concerning road conditions are constantly processed. In a manner known from German Patent No. 195 30 065, for example, an FMCW (frequency modulated continuous wave) radar is attached to the front area of the motor vehicle, and has both the transmitting technology with an antenna system for generating radar beams and a receiver having the evaluation electronics. According to German Patent No. 195 30 065, lateral ascertaining of the position of objects can also be carried out by a multi-beam method.
The speed regulation in an ACC system mentioned at the beginning is done in such a way that the regulation is based on either a setpoint value, i.e. a desired speed, or on the speed of a vehicle traveling ahead, in case the latter is slower than the desired speed, and this vehicle is within detection range of the radar sensor. It can happen here that, even using the ACC system, in the case of right-hand drive traffic, a vehicle may pass improperly on the right. This happens when no target vehicle is present in the right lane that is going faster than a vehicle to the left, or, if it is going at the same speed, it is still at a great distance from the vehicle having the ACC system.
In European Patent No. 0 716 949, for example, in a speed regulation for a motor vehicle, consideration is taken in the regulation of the closest vehicle which is in a faster lane, i.e., in the lane to the left, in right-hand drive traffic. This vehicle then becomes an object of regulation if it goes slower than the target object in one's own lane, or when no target object is present in one's own lane. What is disadvantageous here is that, in a spontaneous great delay in the traffic in the neighboring lane, the vehicle having the ACC system also has its speed braked down strongly.